More than 84 million - or 1 out of every 3 U.S. adults - have prediabetes, a condition that if not treated often leads to type 2 diabetes within five years. Average medical expenditures among diabetics are about 2.3 times higher than expenditures for people without diabetes. Physical inactivity and elevated body mass index (BMI) are major risk factors for the disease. Sedentary behavior is becoming increasingly prevalent with the growth of a 'work from home' culture, most recently driven by the COVID-19 pandemic. Cross-sectional epidemiologic data report significant associations between high amounts of sedentary (sitting) time and prevalent cardiovascular disease and diabetes. In our pilot study of 15 subjects with sedentary office jobs, 6 months of sit-stand desk use resulted in a 23% improvement in insulin resistance, most substantial in those who decreased daily sitting by over 90 minutes/day. Additional improvements in vascular endothelial function and triglyceride levels were seen without any change in exercise activity, step counts, or body weight. These findings not only corroborate epidemiologic findings on this topic but suggest causality and warrant a randomized control trial.

The investigators hypothesize that adult subjects at-risk for diabetes will improve insulin sensitivity, metabolic and vascular (endothelial) health with a sit-stand desk intervention at work (whether in the office or at home), in the context of a randomized, controlled trial. The investigators will randomize 198 sedentary office workers with a BMI≥25 at risk for type 2 diabetes mellitus in a 1:1:1 ratio of three groups: (a) sit-stand desk intervention targeting 2 hours standing per day; (b) sit-stand desk intervention targeting 3 hours standing per day; or (c) control arm over 6 months. The block randomization design will allow for important dose-response analyses.

The investigators will objectively quantify standing time, sedentary time, sedentary bouts, daily steps, and exercise activity times using a compact and re-usable accelerometer that adheres to the subject's thigh. This will provide objective assessments of activity levels and sedentary times for 7 full days each at baseline, 3 and 6 months. The device is equipped with an inclinometer to classify posture (sitting verses standing).

Inclusion Criteria:

1. Overweight or obese (body mass index of 25 kg/m2 or higher)

2. Employees with "sedentary" jobs, defined as spending at least 75% of their (8 hours or more) workday sitting at a desk (at home or in an office)

3. Defined as "at-risk" for diabetes, defined as either:

   1. Prediabetes (HbA1c of 5.7% to 6.4%) or a fasting glucose of 100 to 125 mg/dL

   2. Having one or more additional risk factors: (beyond BMI>25)

      • Age 45 years or older
      • Family history of diabetes mellitus in a first-degree relative
      • Physical inactivity (no structured exercise activity)
      • History of gestational diabetes, hypertension, or dyslipidemia
      • African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, Native Hawaiian, or Pacific Islander ethnicity

Exclusion Criteria:

1. Established cardiovascular disease (myocardial infarction, coronary stent, coronary artery bypass grafting, cardiac transplant, or angina)
2. Established congestive heart failure or cardiomyopathy
3. Established peripheral vascular disease
4. Established diabetes (HbA1c ≥ 6.5% or on diabetes medications or insulin)
5. Chronic musculoskeletal disorders involving the lower extremities, such as arthritis of the knees or hips, or regular use of ambulatory assist devices such as a walker or cane
6. Neuropathy of any etiology
7. Positional syncope or history of orthostasis
8. Less than 4 days/week at any single office (or work-from-home) location.
9. Current use of a standing desk for work
10. Tobacco use within the previous 12 months
11. Current illicit drug use or excessive alcohol use (defined as more than 14 drinks/week for women, more than 28 drinks/week for men)
12. Steroid use ≥21 days/year
13. Fasting triglyceride level ≥ 500 mg/dL
14. Thyroid disease
15. Uncontrolled or untreated hypertension(>150/90 mm Hg)
16. Pregnant or lactating (or plans to become pregnant in the next 6 months)
17. LDL cholesterol ≥ 190mg/dL
18. Currently enrolled or plans to diet or join a weight loss program over the next 6 months.
19. Non-English speaker

Within 1 year of completion of all studies procedures